Biomarker series could help identify suicide risk

A team of researchers from the Indiana University School of Medicine (IN, USA) have recently discovered a series of RNA biomarkers in blood, which may help identify those at risk of committing suicide. The study, led by Alexander B. Niculescu, associate professor of psychiatry and medical neuroscience, demonstrates ‘proof-of-principle’ for a test that could provide an early warning for individuals who are at higher risk for suicidality.

Commenting on the research, Niculescu said, “Suicide is a big problem in psychiatry. It is a big problem in the civilian realm, it’s a big problem in the military realm and there are no objective markers. There are people who will not reveal they are having suicidal thoughts when you ask them, who then commit it and there is nothing you can do about it. We need better ways to identify, intervene and prevent these tragic cases.”

The scientists first looked to identify blood gene expression biomarkers for suicidality, identifying differential expression of genes in blood of those subjects with a major mood disorder, in this case bipolar disorder, which is a high-risk population prone to suicidality. Blood samples were taken every 3–6 months from a large group of patients over a 3-year period, while interviews were also conducted with participants who indicated shifts ranging from no suicidal thoughts to strong suicidal ideation. Differences in gene expression between the ‘low’ and ‘high’ states of suicidal thoughts were identified, and the findings subjected to convergent functional genomics analysis, which identifies and prioritizes the biomarkers by cross-validation with other lines of evidence. From this analysis, the marker SAT1 was identified as providing the strongest biological signal associated with suicidality, along with a series of other markers.

The group’s findings were validated by working alongside the coroner’s office, analyzing blood samples from suicide victims and finding that some of the same markers were significantly elevated. Blood analyzed from two additional groups of patients also unveiled that high levels of the markers correlated with future suicide-related hospitalizations and also hospitalizations that occurred prior to the tests.

Concluding, Niculescu stated, “This suggests that these markers reflect more than just a current state of high risk, but could be trait markers that correlate with long-term risk.” However, he also noted a limitation within the work, in that all the research subjects were male. “There could be gender differences. We would also like to conduct more extensive, normative studies in the population at large. Nonetheless, these seem to be good markers for suicidal behavior in males who have bipolar disorders or males in the general population who commit impulsive violent suicide.”